Pantographic machine tool



Feb. -26, 1929.l 1,703,421

F. P. HABlcH'r.

PANTOGRAPHIC MACHINE TOOL Filed NOV. 17, 1925 coc- A TToRNeYs.

Patented Feb. 26, 1929.. l'

f UNITED STATES N lO FFI C FRANZ PAUL ,H iBIcH'r, oF scH'AFFHAUsEN, SWITZERLAND.

PANTOGRAPHIC MACHINE firooL.

Appucaaon ined November 17, 1925, serial No.' 69,619, and nrswitzeriaai'Nvember 2o,` 1924.

Pantographic machine tools are known with which the tool, tor instance an engraving tool7 is controlled by the pantograph and is driven by cords andcoro pulleys. Such machines which are mostly-used tor engraving are not suitable for heavy duty. The reason is that the joints ot the pantograph as well awthe links ot the `latter are subject to vibrations. An accurate milling or plane sur-A graph, causea parallel guidance in a similar manner as a cross sliding table provides for the possibilities which are otherwise only inherent to machines having cross sliding't'a.- bles. n Multiple spindle machines may be used and copying devices vof the known type may kbe employed.

The arrangementof the machine is as fellows:

stantially horizontal. For instance theupper plate may slide on thelower plate and may be pressed against the latter by its weight.A

One ot the plates is controlled bytwo pantographs which have the same ratio and fone steering point common to both. Vl`he pantographs and their operative connecting points :tor instance on the upper plate are soarranged that during a. movementof the steering point along a. curve the controlled plate carries out parallel movements so that with a certain imweme'nt'otl the steering pointeaoh point of the plate moves on a curve similar to the atorc mentioned curve and that the movement ofthe plate effects the control ot' the machining performed on at leastone blank. n

pposite the plate, spindles may be arranged provided with gripping devices adapted to tix rotarj cutters or blanks to be turned, which may be rotated by belts7 electric motors and the like. The plate itself may support gripping devices by means ot which blanks to be milled, lathe tools, screw cutters and the like may be lixed to the plate. In case the present pantographio machine tool is used as a milling machine one or more Two plain plates, one sliding upon the other, are provided the plane of which 1s submilling spindles with substantially vertical axes may be provided. They `may be adjustable in -height by means of known slides guided in supports. ,Y

In using thc machine tool as a lathe one or more spindles with substantially horizontal axes may bearranged. l? or special purposes, tor instance in thelapplication as turning and millingmachine both types of the positions ot the spindlesr or intern'iediate ypositions may be used.

Two constructional examples7 one relierring toI acmilling'machine and the other to a turning lathe, shall 'now be described. Figs'.

`l, 2 and 3 illustrate the milling machine in elevation, plan view andend view yrespectively,V and f f Figs. 4, 5 and 6 are views similar to Figs. 11, 12 vand 3 respectively, but illustrating a at ie. Y

vating handle le is provided. Above the'l plate c the milling spindles g are mountedinv adjustable slides AThe spindles are rotated by the belt drive L. The adjustment of the rheight of the milling spindles'fmay 'be made in a known manner by means of a vernier or a micrometerdisc.VIK The operating handle 73 of the pantographs is arranged above a vtable mA onwhich drawings or templates may be tired. c ln the present example'it is as-v sumed that the machine has to pertorm milling work; ln order to avoid errors and to attain the greatest accuracy the pantographs b and 1 have only one ratio 'whilst in case of the machine being used as an engraving machine several ratios are preferably used. The plate c is comparatively heavy'. It also has avery large surface with which to bear on the lower stationary plate. By means of a small amount Aof oil or grease pressed in between the two plates the latter adhere stronglyv to each other and in spite of the large'weight an easyV movement is ensured. When the pantograph steering point 4is guided along a curve the centre of the end mill will describe a similar curve on the plate 0 but on a different Scale. The accuracy with Y On the'stationary horizontal plate, athe eov and on the clearance in the joints as well as on the magnitude of the vibrations vvvhichthe movement of the milling spindle transmits to these parts. The large weight of the plate c ensures that these vibrations .are scarcely noticed atthesteering point. It is easy to keep the clearance in the joints below three hundredths of a millimetre and it is there foreeasily possible to attain a lateral accuracy of the present machine tool of less than one tenth of one millimetro. A proper mounting of the milling spindle g is ot vital importance and it may he attained. for instance by utilizing amply dimensioned hall bearings. The obtainable accuracy in depth depends practically only on the heating` and on the clearance in the bearings oft the milling spindle g. lt may be easily kept within one hundredth ot one millimetre. As may be seen from 'the drawings with the machine illustrated two blanks may be simultaneously machined. However, more than two spindles may be arranged without departing from the principle of the present invention.

. In the structure shown in Figs. a, 5 and .6, A denotes a stationary horizontal plate on which the plate C can he displaced by means of the pantographs B and B1. Cn the plate C various tools D are liXed by means of the gripping devices E. Opposite the plate C turning spindles G having blanks lT fixed to them are arranged. The 'lathe spindles are driven by the belt drive H. All the other parts correspond to those illustrated in Figs. l, 2 and 3. AS will be seen from the drawings such a pantograph lathe replaces a two spindle turret lathe. It is, however, more stable and cheaper. Curved' Ablanks may easily be machined, for instance handles for tools and machine tools.

As the two pantograph's with their common vsteeringl point permit the plate C to carry out parallel movements and guide the latter as it' the plate were 'sliding in a cross slide, obviously both types of machine tools, i. e. the lathe as wellas the milling' machine, may be utilized as copying machines in a known manner. Thereby the advantage presents itself that instead of two controlli'ng` levers, which are necessary with the known ,copying machines, the operation 'ot the 'steeri'ngjpoint of the pantograph maybe "per- .formed by a single handle. Vhen "copying,

the' panto'graphs may be used' as parallel guides and as mechanisms'causing the movement whilst the control may be eiilected in a known mannerv by a 'eeler pin and a speci# men work piece.

The novel machine may obviously be also used as a grinding machine.

Claims: Y

l. A pantographic machine tool, compris ing a pair ot' plates of substantially heavy weight one slidabl-e upon the other, a pair o v equally proportioned pantographs pivotally 'connected to said plates and adapted to opermovement of the steering member is dupliy cated by the slidable plate, and a plurality ol rotatable spindles disposed adjacent to said slidable plate and 'adapted to cooperate therewith to operateupon a piece of work.

3. A pantographic machine tool, compris# ing' a pair oli' plates of substantially heavy weight one slidable upon the other, a pair of 'equally proportioned pantograph's pivotally connected to said plates and' adapted to operate saidslidable'plate, 'a common steering member l'or operating` said lpantographs in unison, the organization being such that any movement of the steering member vis duplicated by the slidable plate, a rotatable spindle disposed in juxtaposition to said slidable plate, means carried by the plate for curing` a piece. of work thereto, 'and Vmeans carried Said spindle for holding 'a tool in position vto operate 'on said piece 'ol work in response 'to the operation 'of said steering member.

In testimony whereof I have signed my naine to lthis specification.

.FRANZ PAUL HABCHT. 

